This invention relates to tool holders, and is more particularly directed to a quick-release holder for holding machine tools such as drills, routers, reamers, etc. The invention is also directed to a multiple spindle head that employs such quick-release tool holders.
A number of quick-release type mandrels or spindles for machine tools have been previously proposed, with their object being to facilitate interchange of one tool with another tool, and to hold tools in a precise predetermined position in the tooling machine.
One class of these previously proposed tool holders employs balls or ball-like retaining devices which enter recesses in the shank of a tool or fitting on the tool. Devices of this type appear in U.S. Pat. Nos. 2,384,600 to Cherry; 3,708,178 to Lauricella; 3,747,946 to Edens; and 3,741,573 to Treer. In these devices the spherical-surface gripping balls do have some play in the machine tool recess when in the engaged position so large manual forces on a change-over handle are typically needed to ensure proper seating. This means that either a handle must extend outward from the holder, or else a separate wrench is required. In the former case, the handle can disturb the rotational stability of the head, thereby limiting the unit to very slow speed use. In the latter case, the requirement of a separate wrench significantly reduces the effectiveness of the quick release or quick change feature.
Moreover, Applicant is unaware of any multiple-spindle tool holder, i.e., in which the machine tool output shaft provides rotary power to a number of rotary machine tools, and which also incorporates quick-release mechanisms for the various spindles so that the tools can be quickly interchanged.